Amplifiers are used for amplifying input RF signals to receivers such as TV tuners, multimedia tuners, and tuners for PCs.
Presently in a TV tuner (TV set), for example, there exist different types of amplifiers, for example, a low-noise amplifier (LNA) type amplifier with a bypass, or a power splitter type amplifier.
These two concepts have been used until today by most of the TV set manufacturers, but both concepts have disadvantages. An LNA, for example, with a high gain and low noise, is not able to handle normal cable TV signals, and a power splitter amplifier that is able to handle such signals has relatively high noise. These two drawbacks cause problems, for example, when a TV set should be connectable to both a cable TV system and a conventional antenna and at the same time provide a high quality.
JP-A-10084500 describes a LNA for improved sensitivity especially for low-level signals with a sensor for a certain threshold. The LNA can not be used as a splitter for strong cable signals, for example, since the bypass suffers from implementation loss.